How Do Robotic Lawn Mowers Work

How Do Robotic Lawn Mowers Work


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How Do Robotic Lawn Mowers Work

As you may already know by now, robotic mowers are designed so you don’t have to do lawn mowing ever again. You may even know that they can do a better job than you, that they don’t need your help and that they can recharge themselves automatically. Not to mention that they are safer and cheaper in the long run compared to petrol mowers, they conveniently work to suit your lifestyle, provide a great looking lawn all year round with no grass clippings for you to worry about.

Well this may leave you wondering how? How exactly can they do all this?

It’s a good thing you dropped by, because that’s exactly what I’m going to talk about in this article.

How a robotic mower operates is essentially broken up into three different factors – the Navigation System, the Charging System and the Cutting System. To form a basic understanding of these mowers, you should become familiar with these aspects.

And even though all mowers are different, you can rest assured these factors are still there. Even though they may have some alterations and additional features depending on the model you choose, but on the whole most models are very similar.

That is why you should get to know them inside-out (well maybe not that in-depth but definitely to have a basic understanding). Because they’re so similar it can be difficult for you to decide which one to choose as the best suitable option for you and your lawn. After reading this post you’ll be able to make better comparisons between robotic mowers, which will hopefully lead to you finding the perfect one.

Navigation System

How Do Robotic Lawn Mowers Work - Navigation System

Just like cars, some robotic mowers use GPS to navigate. In order for the mowers to drive around your lawn unattended, they are going to need some sort of guidance. But don’t worry this isn’t from you, it’s actually from a wire.

It may sound unusual but yes a wire. Let me explain…

Perimeter Wire

So that the robotic mower gets an idea and picture of your lawn stored in its memory system, you are required to run a perimeter wire around your lawn. If you have any obstacles in your garden and want to prevent your robotic mower going there, you will have to section this area using the wire. For most people this would be around the flowers beds, plants and trees. It’s pretty much for anything you don’t want the mower getting access to.

The wire will now act like an invisible fence by sending an electrical signal to the mower, letting it map out your entire lawn. The mower will then begin calculating a route to follow using the information.

Once done it will get to work and starting mowing. Most robotic mowers have the ability to learn, so over time they become more cleaver and efficient in their mowing route.

And just in case it runs into any obstacles while following that route (toys, trampoline etc), it has sensors to deal with them. These make sure the mower does not continue pressing forward. Instead it will stop, turn off the blade, recalculate, turn around and begin mowing in a different direction.

This not only prevents damage to the robotic mower and the obstacle, but also makes sure no one is harmed while it’s working.

The Best Robotic Lawn Mowers for Your Garden

If at this point you have already decided that a robotic mower is the right choice for you and your lawn, for your convenience below I have included the best robotic mowers I have tested for small, medium and large gardens. Each review will provide in depth information, pros / cons and who the mower is suitable for.

Best Robotic Lawn Mowers

Last update on 2022-06-30 / Affiliate links / Images from Amazon Product Advertising API

You will need to ensure that the mower you are considering can cover the lawn size you have and meets your requirements in terms of functionality.

Add-On Features

How Do Robotic Lawn Mowers Work - Add-On Features

Many of the latest robotic mowers now have the ability to be expanded and enhanced through a series of optional modules that can be inserted to your robotic mower. All robotic mowers will come with a basic collision detection system, which means when they bump into an obstacle they will stop, reverse and carry on mowing in another direction. Now more advanced proximity sensors can be added to your robotic mower, so they can “see” an obstacle before bumping into it. This helps to ensure that the robotic mower can cut to the edge of the obstacle and does not interfere with the mowers cutting pattern.

Other add-ons include “Off Limits” sensors, which means you can run a single stand alone wire around an obstacle such as a flower bed and the mower will avoid these areas.

There are other features that allow greater control over your robotic mower such as enhanced GPS functionality.

Why is the ability to expand your robotic mower a good thing? Well, because you can start with a basic model and see if this works well and suits your needs If however you want to upgrade or have moved and your garden circumstances have changed, you have the option of adding these extra features to protect your investment.

Multi Zone Capability

How Do Robotic Lawn Mowers Work - Multi Zone Capability

If your garden has multiple lawn areas you will want to ensure that your new robotic mower has a multi zone feature. You will need to ensure that the perimeter wire can be run from the primary lawn area to the secondary lawn area via a passage (can be over a driveway or path). You need to ensure that this passage is level and wide enough for the robotic mower to navigate. Alternatively, some robotic mowers will allow you to lift the mower to the secondary area and then return to the primary area for charging.

If you have an area of your lawn that requires special attention, you can let the mower know that this is the area you want it to focus on via the app or iPad.

So there you have it. The robotic mower runs around your lawn with the guidance of an invisible fence, uses a pre-determined route and gets help from on-board sensors to stop it from running into anything.

Charging System

Just like every electrical gadget right now, the robotic mower comes with a charging base station. This is not any charger like a cable you would plug into a socket, these mowers have their own docking station that they automatically return to when they need charging.

This means that not only does it cut your lawn by itself, but it will also charge itself as well. So you won’t have to plug it in every night before you go to bed.

Whenever the mower begins to run low on power while mowing, it will automatically make its way back to the station to recharge. And when its battery is full again, it will lead itself back out to the exact point where it last left off. Completely and conveniently removing you from the process. This of course is much easier and effortless compared to a traditional push lawn mower.

How Do Robotic Lawn Mowers Work - Charging System

Furthermore, you don’t have to worry about the robotic mower getting lost in your garden during its mowing routine. The docking station is attached to the perimeter wire, which the mower can use as a guide.

Charging and Run-Time

Charging and run-time will vary from one robotic mower to another and you will just need to ensure that these are adequate in order to cover the size of your lawn.

Most robotic mowers now come with lithium-ion batteries (latest technology) as opposed to led batteries (old technology) and will normally take around 1 hour to charge providing the same amount of run-time on most domestic models. Higher end models will provide longer run-times. You don’t really need to worry about the charging time as your robotic mower will work when and how you want it to work. If you prefer it to work at night only, then you can schedule it to do so. Just remember if you have steep inclines in your lawn, this will drastically reduce the run-time of the robotic mower. In these situations you may want to consider a robotic mower that has a higher capacity battery and a better ability to deal with steeper slopes.

How Do Robotic Lawn Mowers Work - Charging and Run-Time

Another point worth noting is that you may notice that some robotic mowers that are identical have the same battery capacity, but are designed for larger lawns. This is purely down to how long they have been programmed to run each day and how much perimeter wire is supplied with the mower.

So you really don’t need to worry about robotic mowers, they do all the work once they are set up and running. The installation and configuration can be done by anyone with basic DIY skills. The only thing you will need to worry about is relaxing after a stressful day at work. It really is up to you how you use this extra time, but just remember that the robotic mower should be thanked for it.

Robotic mowers really are great machines.

Cutting System

The cutting system, or the manor to which these machines cut, is quite unique. Most electric or petrol mowers are designed to take off long pieces of grass so you don’t have to mow as regularly. During summer it is recommended that your lawn is cut once per week with a traditional push mower. On the other hand robotic mowers have a much better and practical way of cutting your lawn.

They are programmed to cut tiny little grass clippings instead. This may take longer for you to notice any real difference, but the reasons behind it are actually very simple and very effective.

Firstly, because the grass clippings are so small they fall down to the bottom of your soil. This is where the magic happens. There they’ll decompose to act as a natural fertilizer (or mulch), passing on nutrients, making the soil moister and healthier. This produces a much healthier, stronger and thicker grass growth, which in turn makes your lawn look much greener and fuller.

I don’t know about you, but I bet that a traditional push mower couldn’t do that! Of course, you could purchase petrol and cordless mowers with mulching function, but again the difference still remains in the frequency of cutting.

So over time you’ll begin to notice that your garden is looking better than it ever did before.


How Do Robotic Lawn Mowers Work - Blades

In general there are two types of blades fitted to robotic lawn mowers. Some will have a larger single cutting blade such as on the Robomow robotic mowers, others will have a number of small rotating razer blades, these are more common and can be found on the latest domestic robotic mower models. As with everything there are advantages and disadvantages to both systems.

The small rotating blades are very lightweight, give a sharp precise cut and are lighter compared to the singular larger blade. Being lighter helps to preserve the battery and increase the mowers run-time. The disadvantages of these smaller blades is that they are not as long lasting and can become blunt within a few months, and therefore will need to be replaced. The good news is that these blades are relatively cheap and replacing them is a quick and easy task.

Whilst on the subject of blades some robotic mowers have what is known as “Floating Decks”. It is my experience that a floating deck is by far more superior as it tends not to suffer from issues of getting stuck when working on uneven surfaces.  A Floating Deck means that the blade mechanism has the ability to move up and down and therefore “ride” any bumps more easily without getting beached.


How Do Robotic Lawn Mowers Work - Slopes

Let’s not forget that robotic mowers are able to deal with steeper slopes in your garden too. Some robotic mowers are 3 wheeled, others are 4 wheeled (more powerful models). Depending on the slope in your garden, and struggle that you would normally experience with a standard push mower, again this is something you will no longer need to worry about.

These really are incredible machines and they’re no match for the conventional push mower. There’s nothing else that can compete with the results of the robotic lawn mower. Simply said, they’re just too good.


And there you have it, you now have a basic understanding of how robotic mowers operate. Which means it’s time for you to move onto the next stage… finding the perfect robotic mower for you.

Now I don’t mean aimlessly reading through all my reviews straight away, I actually have another article to help you through this process. This may sound quite simple to do, but there are a few factors that you’ll need to consider before purchasing, and it can in fact be a little overwhelming.

So to make it easier on yourself, I would recommend that you read my article How to Pick the Perfect Robot Lawn Mower. Here I go through every consideration you’ll need to make (size, slope, complexity, price, practicalities), explaining how one decision may affect the other and what you should look for in a robotic mower.

If you are still not convinced about purchasing a robotic mower, I would recommend that you read my article Reasons Why You Should Buy A Robotic Lawn Mower.

I hope you enjoyed the read and if you need any more help or guidance, then please leave a comment below. I will be happy to respond.


8 thoughts on “How Do Robotic Lawn Mowers Work

  1. The thing that confuses me most about robotic mowers is the charging. I don’t understand how the robotic mower will plug itself in. My wife and I have been talking about getting a robotic mower with GPS since we have a large property, I just want to see how it works.

    1. Hi Michael

      Thanks for contacting me. Take a look at this video as it covers the basics of how these robotic mowers work.

      It is for a Flymo Robotic Lawnmower 1200R but all work pretty much the same way and it shows the charging station in action.

      If you do decide to go ahead then you will need to find a robotic mower that best suits your lawn/garden and your budget.


    1. All robomowers have a boundary wire laid around the borders of their lawns, this sends out a signal to the mower which tells it of its mowing/working area. With this in place the mower will map out every inch of grass which needs cut and therefore will be able to calculate where it has and hasn’t been during a mow.

      Yeah for most models their movement pattern is quite random but they still ensure that all bits of grass are cut within the main working area.

      Thanks for the question John, I hope this helps and if you have any more questions then please just ask ;-)

      1. Hi Mark,

        I found your blog by accident as I am interested in purchasing a robot lawn mower and have found your articles interesting. I have a question that I was wondering if you could help me with.

        My property does not have an external wall socket in the garden for me to plug the charge point of the robot lawn mower in (if I do purchase one).

        I was wondering if I could get by instead by using an extension lead out to the garden for whenever I wanted the mower to charge and mow rather than getting an electrician in to install a permanent external wall socket?

        Your thoughts on this would be appreciated.

        1. Hi Adrian,
          You will either need a water proof socket on the outside or the wire will need to be run inside to a suitable socket. You will not be able to use an extension lead unfortunately for safety reasons.

  2. Wow this is really fasinating. I’ve never heard of robomowers before. So these are different then the ones you drive around, these you just set amd they go on their own. It’s so cool that some have a gps and they have a wire so they know where your lawn is
    How much do these things generally cost?

    1. Yeah they really are cool machines. For most models, they’ll be priced anywhere from £1,000 to $3000 but you can get cheaper ones for under £1000. Just make sure to have a good look around before you buy, this will make sure you get the cheapest price. You’ll probably have the best luck trying out Amazon or eBay so I recommend going there first.

      Thanks for the comment and if you need any help then please just ask :-)

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